Stud tensioning and tighetning apparatus

Abstract

Tensioning and tightening apparatus for a conventional stud and nut wherein a piston and cylinder pair defining a pressure chamber are disposed beyond the end of the stud rather than in the form of an annulus around the stud and the tensioning force is transmitted by tension-bearing members extending through the piston and cylinder pair to a puller attached to the stud but not through the pressure chamber.

I claim: 
     
       1. Tensioning and tightening apparatus for a stud projecting from an opening in a surface through and beyond a closure nut threaded thereto comprising (a) a puller adapted to be screwed onto the stud beyond the nut,   (b) a spacer sleeve coaxial with and surrounding the puller and adapted to abut said surface around the opening,   (c) a telescoping piston and cylinder pair coaxial with the sleeve at that end thereof remote from said surface and together defining a pressure chamber through which the stud axis extends,   (d) one of said piston and cylinder pair being remote from and the other being adjacent to said end of the sleeve,   (e) a plurality of tension-bearing members connecting and preventing movement apart of the puller and that one of the piston and cylinder pair which is remote from the sleeve and extending slideably through corresponding holes in that other of the pair which is adjacent the sleeve but not extending through the pressure chamber,   (f) pressurizing means for forcing the piston and cylinder apart to tension the stud,   (g) access means in the spacer sleeve permitting the nut to be screwed down on the tensioned stud into contact with the surface, and   (h) biasing means for moving the piston and cylinder together when the chamber is depressurized.   
     
     
       2. Tensioning and tightening apparatus according to claim 1 wherein the spacer sleeve is longer than the length of the stud projecting from said surface. 
     
     
       3. Tensioning and tightening apparatus according to claim 1 wherein the cylinder is adjacent the sleeve and the piston is remote from the sleeve. 
     
     
       4. Tensioning and tightening apparatus according to claim 1 wherein the biasing means are springs. 
     
     
       5. Tensioning and tightening apparatus according to claim 1 wherein the tension-bearing members are rods. 
     
     
       6. Tensioning and tightening apparatus according to claim 5 wherein the rods are equally spaced around a circle larger in diameter than the cross section of the pressure chamber. 
     
     
       7. Tensioning and tightening apparatus according to claim 1 wherein the pressure chamber is circular in cross section. 
     
     
       8. Tensioning and tightening apparatus according to claim 7 wherein the circular cross section of the pressure chamber has a diameter greater than that of the stud. 
     
     
       9. Tensioning and tightening apparatus according to claim 1 wherein the movement apart of the piston and cylinder during pressurization is limited by contact between the puller and that one of the piston and cylinder pair adjacent the end of the sleeve, thereby permitting pressure testing of the apparatus without assembly to the stud. 
     
     
       10. Tensioning and tightening apparatus according to claim 1 wherein the sleeve and that one of the cylinder and piston adjacent the sleeve are two separate interconnected parts. 
     
     
       11. Tensioning and tightening apparatus for a stud projecting from an opening in a surface through and beyond a closure nut threaded thereto comprising (a) a puller adapted to be screwed onto the stud beyond the nut,   (b) a spacer sleeve coaxial with and surrounding the puller and adapted to abut said surface around an opening and being longer than the length of the stud projecting therefrom,   (c) a telescoping piston and cylinder pair coaxial with the sleeve at that end thereof remote from said surface and together defining a pressure chamber of circular cross section larger in diameter than that of the stud,   (d) the cylinder of the piston and cylinder pair being adjacent the sleeve and the piston of the pair being remote from the sleeve,   (e) tension-bearing rods equally spaced around a circle larger in diameter than that of the circular cross section of the pressure chamber and connecting and preventing movement apart of the puller and the piston and extending slideably through corresponding holes in the cylnder but not through the pressure chamber,   (f) pressurizing means for forcing the piston and cylinder apart to tension the stud,   (g) the movement apart of the piston and cylinder being limited by contact between the puller and the cylinder thereby permitting pressure testing of the apparatus without assembly to the stud,   (h) access means in the spacer sleeve permitting the nut to be screwed down on the tensioned stud into contact with the surface, and   (i) compression springs around the respective rods and acting between the puller and the cylinder for moving the piston and cylinder together when the chamber is depressurized.   
     
     
       12. Tensioning and tightening apparatus for a stud projecting from an opening in a surface through and beyond a closure nut threaded thereto comprising (a) a puller adapted to be screwed onto the stud beyond the nut,   (b) a spacer sleeve coaxial with and surrounding the puller and adapted to abut said surface around the opening,   (c) a telescoping piston and cylinder pair coaxial with the sleeve at that end thereof remote from said surface and together defining a pressure chamber,   (d) one of said piston and cylinder pair being remote from and the other being adjacent to said end of the sleeve,   (e) tension-bearing members connecting and preventing movement apart of the puller and that one of the piston and cylinder pair which is remote from the sleeve and extending slideably through corresponding holes in that other of the pair which is adjacent the sleeve but not extending through the pressure chamber,   (f) pressurizing means for forcing the piston and cylinder apart to tension the stud,   (g) access means in the spacer sleeve permitting the nut to be screwed down on the tensioned stud into contact with the surface, and   (h) compression springs around the respective tensioning rods and acting between the puller and the piston and cylinder pair for moving the piston and cylinder together when the chamber is depressurized.